The present invention concerns a drive for a movable furniture part, comprising an adjusting member for moving the furniture part and a motor for driving the adjusting member, wherein the adjusting member and the furniture part are at times movable independently of each other.
Drives of the general kind set forth are already known, in which the position or movement parameters derived therefrom of the adjusting member or the movable furniture part can be determined by way of a position measuring device.
For example WO 2006/017864 A1 on pages 5 through 6 (fourth variant of the invention described in WO 2006/017864 A1) describes a drive for a movable furniture part comprising a position measuring device by which the position of the adjusting member (ejection lever) can be determined. In addition, the above-indicated specification on page 7 thereof describes the possibility of coupling the position measuring device to the furniture part itself, instead of to the adjusting member. In the embodiment shown in FIGS. 18 and 20, that is effected either by way of a spring-loaded thrust member or by way of an entrainment member which can be coupled to the movable furniture part over a certain distance.
The state of the art suffers from the problem that it is not possible to detect the position or movement parameters derived therefrom selectively or simultaneously both for the furniture part and also for the adjusting member. More specifically, the position and movement cannot be detected independently of whether the adjusting member is or is not just in contact with the furniture part.
The object of the invention is to overcome that problem, and is attained by a drive having the features described below.
There can be various reasons why the adjusting member and the furniture part are at times movable independently of each other. For example, the adjusting member, for moving the furniture part, can loosely contact the furniture part. That situation arises when the adjusting member is in the form of an ejection lever or thrust member. More specifically, the ejection lever or thrust member bears against the furniture part only over its pivotal or extension travel.
It can, however, also be the case that the adjusting member in itself is fixedly connected to the furniture part but a coupling is arranged in the drive train between the motor which drives the adjusting member and the furniture part, wherein the drive train can be disengaged by the coupling. It may be desirable, for example, if the movable furniture part is movable manually by a user without—in that case—the user being impeded by the motor. That is advantageous if the motor is defective or the user for example wants a higher speed than that of the furniture part when driven by the motor.
It can, however, also be the case that the coupling is in the form of an overload coupling to avoid damage to or destruction of the adjusting member or the motor. Without such an overload coupling, the adjusting member, when the movable furniture part is loaded with excessive forces, can transmit those forces to the motor or a transmission.
In regard to all those possible options, it is possible with a drive according to the invention to determine the position or movement parameters derived therefrom (such as speed or acceleration) of the adjusting member and/or the furniture part, even if the adjusting member and the furniture part are just moving independently of each other.
The fact that the position or movement parameters derived therefrom of the furniture part can be continuously determined means that it is, for example, possible to constantly maintain a touch-latch functionality with respect to the drive. This means that a user can cause activation of the motor by the application of a force to the furniture part and the change in position or speed of the furniture part, that is caused thereby. That is desirable, in particular, when the motor is active only over a part of the total travel of the furniture part in order to again trigger the motor.
The effect of determining the position or derived movement parameters of the adjusting member can also be used on the one hand to implement a touch-latch functionality. In this case, for example, the motor is activated upon a change in the position or speed of the adjusting member.
On the other hand, the motor can also be intended by way of the adjusting member to implement a predetermined travel, speed, or acceleration profile for the furniture part. To permit the dependency on the position or speed or acceleration in regulated relationship, it will be appreciated that there must be a suitable position measuring device and possibly a clock and a computing unit.
It is also possible to provide for collision monitoring by using the position measuring device. The position (location or travel) of the movable furniture part is measured in that case and monitored by a control or regulating device for a change in speed or acceleration. The operation of ascertaining the speed or acceleration of the movable furniture part can be effected, for example, by forming the first or second derivative of the position in dependence on time. If the change in speed or acceleration differs from a reference value which was established earlier, then the motor can be switched off. Examples of collisions include a user who is standing under a movable item of furniture in the form of a flap and who blocks the closing movement of the flap, or an article projecting from a body or carcass of an item of furniture and which prevents a drawer or flap from closing.
In a particularly preferred embodiment of the invention, the position measuring device can have at least one potentiometer. Particularly preferably, however, there are two potentiometers, in which case a respective potentiometer is associated with the adjusting member and the furniture part, respectively. Absolute position determination can be effected by potentiometers. However, purely incremental position determination may also be adequate for the invention.
It is particularly preferably provided that the motor is in the form of an electric motor.
If control or regulation of the drive is desired, it will be appreciated that a control or regulating device must be provided, to which the signals of the position measuring device can be passed.
It will be self-evident that the position measuring device can physically also be in the form of two components which are spatially separate from each other. Alternatively, it is possible to provide a single component with which there are associated two measuring sensors (for the adjusting member and the furniture part) which operate separately from each other.